This relates generally to integrated circuits and, more particularly, to alignment marks and alignment methods for aligning backside components to frontside components.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imagers (i.e., image sensors) may be formed from a two-dimensional array of image sensing pixels. Each pixel receives incident photons (light) and converts the photons into electrical signals.
Modern imagers, and other integrated circuits, are sometimes formed from integrated circuits having frontside and backside components. The accuracy of conventional techniques for aligning frontside components to backside components, which typically rely upon infrared alignment systems not capable of accuracies less than one micrometers, are undesirable in at least some situations.
It would therefore be desirable to provide alignment marks and alignment methods for aligning backside components to frontside components in integrated circuits.